No-till planting is popular for several reasons. No till planting causes minimal soil disturbance and places the seed in optimal soil-to-seed contact for quicker germination. Other factors include weed control, reduced soil erosion, greater moisture control, and a reduction of fuel costs. The use of no-till planting equipment has increased the amount of acreage available for planting. No-till planting is employed over rugged, irregular terrain, such as hilly fields and highway rights of way.
The no-till planter must be sturdy enough to operate under adverse soil conditions and cut through any previous crop residue. The no-till planter must provide a narrow band of tillage to receive the seed. Accurate control of the planting depth is required, according to soil condition, moisture content and type of seed. The individual planter assemblies on the planter must have the ability to individually negotiate high hills and deep holes, and to withstand side-to-side deflection forces.
A seed drill of the prior art includes a wheel mounted frame for towing behind a tractor. The frame carries one or two ranks of planter assemblies. Each rank is mounted on a transverse mounting bar or rock shaft connected to the frame. See U.S. Pat. No. 4,030,428 issued Jun. 21, 1977 to Truax. Each planter assembly is connected to the rock shaft by a torsion joint and a torque arm connected to the torsion joint. The torsion joint includes a generally square housing that surrounds the shaft, and resilient torsion spring elements positioned in the interior corners of the housing bearing against a flat surface of the rock shaft for compression upon rotation of the planter assembly with respect to the rock shaft. See U.S. Pat. No. 4,977,841 issued Dec. 18, 1990 to Truax.
During operation, the individual planter assemblies can experience considerable up and down movement. Extreme rotational movement of the torsion joint on the rock shaft has a tendency to dislodge or move the torsion joint housing to an over-center position on the rock shaft. If a planter assembly is maintained for any period of time in a position rotated with respect to the mounting bar, as in storage or during transport, there is a tendency for the torsion elements to xe2x80x9csetxe2x80x9d or assume a permanent deformation. For these reasons structure to limit permissible rotation of the torsion joint on the rock shaft is desirable.
The rugged terrain traversed by the no-till planter subjects the mounting beam structure connecting the planter equipment to the main machine frame to considerable side-to-side flexure forces, or horizontal forces. It is necessary to permit some amount of flexure to avoid damage to the machine. However, the mounting structure needs to be strong enough to endure such flexure without damage, yet have substantial resiliency to return the planter equipment to the proper operating location.
On such machines, a seed tube connects the seed hopper to a seed drop or planting shoe that is typically located closely adjacent a furrow opening disk and just behind the working edge that opens a furrow. Up and down movement of the planting equipment over the irregular terrain causes a continuous variation in the distance between the seed hopper and the seed shoe. The seed tube must be sturdy enough to withstand the rigors of a no-till planting environment, yet flexible in length to accommodate the continuously changing distance between the seed hopper and the seed shoe.
Such machines also typically include a depth gauge wheel to regulate depth penetration of the furrowing disk. The wheel is mounted close to the disk and aligned with it. A rubber boot extends from the tire of the depth gauge wheel toward the furrowing disk. The outboard edge of the boot is either spaced slightly from the side of the disk, or is in light surface contact with it. The purpose of the boot is to prevent an accumulation of moist dirt on the side of the disk, which could otherwise inhibit penetration of the disk into the soil. Through wear on the edge of the boot, the gap between the boot and the side of the disk can widen to an unacceptable width. Prior art machines have no ability to compensate for such widening of this gap.
The invention relates to a seed drill or planter for no-till planting. The seed drill includes a wheel mounted frame having one or more transverse rock shafts, each carrying a rank of seed planter assemblies. The planter assemblies are of the type having a torsion joint connected to the rock shaft; a mounting beam or torque arm connected at one end to the torsion joint and at the other end to planting equipment; planting equipment including a depth gauge wheel-furrowing disk combination connected to the other end of the torque arm; and a seed tube extending from a top end proximate a seed hopper, to a location proximate a furrowing disk at the lower end.
The rock shaft has a generally square cross-section shape. The torsion joint is the type having a box like housing that is mounted diagonally on the rock shaft. Spaces formed by interior corners of the housing and the flat sides of the rock shaft are each filled with a bar-like torsion spring element. The torsion spring element bears against the interior corner of the housing and against one of the flat sides of the rock shaft. Rotational movement of the housing relative to the rock shaft results in a return moment produced by deformation of the torsion spring elements.
The planter assemblies have the capacity for a large range of up and down movement relative to the rock shaft by virtue of the torsion joint. Extreme rotation of the torsion joint on the rock shaft tends to dislodge the torsion joint housing on the rock shaft by moving the housing to an over-center position on the shaft. A stop block assembly is provided in order to limit the permissible range of rotation of the torsion joint on the rock shaft. The torsion joint housing includes one side wall comprised as a mounting plate connected to the torque arm. The stop block assembly is assembled to the rock shaft next to the torsion joint housing. The stop block assembly rotates with the rock shaft and includes a stop plate that overlaps with the mounting plate of the torsion joint housing. The stop plate intercepts rotational movement of the torsion joint housing beyond a preselected rotational limit relative to the rock shaft. This not only prevents the torsion joint housing from becoming dislodged on the rock shaft, it prevents the torsion spring elements from acquiring a permanent set as a result of being maintained in an overly deflected configuration.
Torque arms connect the planter equipment to the main machine frame. Certain of the torque arms have a leaf-spring assembly. The torque arms so allow a permissible degree of side-to-side flexure of the planter equipment and bias the equipment toward an undeflected position.
A planter according to the invention can include a seed tube comprised of two or three telescoping sections enabling extension and retraction of the seed tube as may be required according to the terrain being traversed by the associated planter equipment. The first or upper tubular section is fastened to the overall machine frame near the seed bins and is positioned near a seed funnel extending from one or more of the seed bins. The lower section is connected to a frame or yoke carrying the planter equipment. The lower section empties to a seed drop shoe next to the furrowing disk to deposit seed in the seed slot formed by the disk. The seed tube can include an intermediate section connected by a flexible link or tether to the machine frame and telescopically engaging both the upper and lower sections.
A planter assembly according to the invention can also include a depth gauge wheel and furrowing disk combination wherein the lateral distance is adjustable between the side of the depth gauge tire and the side surface of the furrowing disk. A forked yoke is connected to the end of the planter assembly torque arm. One leg of the yoke carries a hub that mounts the furrowing disk. The other leg of the yoke carries a depth gauge wheel assembly that includes another hub that mounts a depth gauge tire parallel to the furrowing disk. The tire is positioned to ride on the soil surface next to the furrowing disk and regulate the depth of penetration of the disk into the soil. A boot extends from the side of the tire to a location with the outboard edge of the boot closely proximate or in light surface contact with the facing surface of the disk. The purpose of the boot is to prevent an accumulation of moist soil on the surface of the disk. As the planter assembly traverses the ground, the boot edge continuously moves into and out of contact with the side surface of the furrowing disk. Eventually the edge of the boot wears away, enlarging a gap between the boot edge and the disk surface. The depth gauge wheel is mounted on a movable axle that is laterally adjustable whereby the distance between the tire and the disk is adjustable. When the boot edge wears away, the tire is adjusted so as to be closer to the disk in order to close the gap whereby the boot again functions properly.